scholarly journals Morphological and molecular variability of Peridinium volzii Lemmerm. (Peridiniaceae, Dinophyceae) and its relevance for infraspecific taxonomy

2021 ◽  
Author(s):  
Victoria J. C. Holzer ◽  
Juliane Kretschmann ◽  
Johanna Knechtel ◽  
Paweł M. Owsianny ◽  
Marc Gottschling
Keyword(s):  
Morphological Variability ◽  
Light And Electron Microscopy ◽  
Intraspecific Variability ◽  
Sister Group ◽  
Integrative Approach ◽  
Molecular Tree ◽  
Reproductive Unit ◽  
Characteristic Species ◽  
Close Relatives ◽  
Unusual Shape

AbstractContemporary delimitation of species and populations in the microbial domain relies on an integrative approach combining molecular and morphological techniques. In case of the dinophyte Peridinium volzii, a considerable number of infraspecific taxonomic entities have been reported, but it is unclear at present whether the corresponding traits are stable within reproductively isolated units or refer to intraspecific variability. We established 26 monoclonal strains from Central Europe with a morphology that is consistent for P. volzii and characterised them by sequences gained from the rRNA operon. Ten of such strains, representative for the entire diversity observed, were investigated in detail morphologically using light and electron microscopy. In the molecular tree, P. volzii was monophyletic, sister group of Peridinium willei, and three ITS ribotypes could be distinguished. Some traits corresponding to previously described varieties and forms were found in individual cells across the strains under investigation, but not as stable characters correlating to certain ribotypes. We also observed new morphological variability (e.g., unusual shape of plate 4″). Cell size and displacement of the cingulum were significantly different between certain ribotypes but in turn, such diagnostic traits are impossible to assign to already described taxa due to their ambiguity. Based on the small first apical plate as diagnostic trait and putative apomorphy, P. volzii is a characteristic species but the present data given, we are reserved to accept more than a single reproductive unit. Thus, more research is necessary, including a focus on species delimitation to putative close relatives such as Peridinium maeandricum.

Morphological and genetic variability of Baetis (Rhodobaetis) braaschi Zimmermann, 1980 (Ephemeroptera: Baetidae)

Zootaxa ◽  
2012 ◽  
Vol 3323 (1) ◽  
pp. 27 ◽  
Author(s):  
PAVEL SROKA ◽  
ALEXANDER V. MARTYNOV ◽  
ROMAN J. GODUNKO
Keyword(s):  
Genetic Variability ◽  
Methodological Approach ◽  
Morphological Variability ◽  
Geographic Origin ◽  
Intraspecific Variability ◽  
Morphological Data ◽  
Mtdna Coi ◽  
Geographic Regions ◽  
Coi Sequences ◽  
The Individual

Specimens of Baetis (Rhodobaetis) braaschi Zimmermann, 1980 from the three distant geographic regions (Crimean Pen-insula, Eastern Ukraine and Caucasus) are investigated and compared using a methodological approach combining mor-phological and molecular (partial mtDNA COI sequences) data. Intraspecific variability in several morphologicalcharacters is recognized and described, whereas COI sequences are found to be very uniform. The amount and distributionof the changes of COI sequences do not follow the pattern of morphological variability and/or geographic origin of thespecimens. This indicates that analysis of the changes in the COI sequence can contradict the pattern of morphologicalcharacters commonly used for the discrimination of the individual Rhodobaetis species. As a basis for the future taxonom-ic changes concerning subgenus Rhodobaetis, it is advised (where possible) to critically evaluate both molecular and morphological data.

scholarly journals Comparing phylogenetics and linear morphometrics to solve the generic assignment ofParabolinella?triarthroidesHarrington (Trilobita, Olenidae)

2017 ◽  
Vol 91 (5) ◽  
pp. 919-932 ◽  
Author(s):  
Daniela S. Monti ◽  
Viviana A. Confalonieri
Keyword(s):  
Phylogenetic Analysis ◽  
Morphological Traits ◽  
Good Description ◽  
Sister Group ◽  
Integrative Approach ◽  
Original Matrix ◽  
Quantitative Characters ◽  
Phylogenetic Framework ◽  
Methodological Approaches ◽  
Source Of Information

AbstractThe use of different methodological approaches together with an exhaustive qualitative study has helped to recognize important morphological traits to distinguish species in a systematic and phylogenetic framework.Parabolinella triarthroidesHarrington, 1938 was described based on two cranidia from the Quebrada de Coquena, Purmamarca, Jujuy province. The generic assignment ofP. triarthroideshas been questioned by a phylogenetic analysis, which resolves this species as the sister group ofBienvilliaClark, 1924. To explore the generic assignment of this species, a revision of the type material, plus a morphometric analysis including specimens ofParabolinellaBrøgger, 1882 andBienvilliawere performed. In addition, the original matrix used in the published phylogeny was reviewed and enlarged, including more species ofBienvillia. Continuous characters were coded in different ways in order to compare how they could affect the ordering of specimens and their phylogenetic relationships. Finally, both methodologies were compared, especially in regard to the behavior of the quantitative characters included in the analyses. From the combined analyses, it is shown that similarities between the cranidium ofP. triarthroidesand all otherParabolinellaspecies are true homologies instead of a by-product of evolutionary convergence. Therefore,P. triarthroidesshould be considered a member of this genus. Finally, this study demonstrates that the best strategy for solving systematic problems in groups where the morphological variation is the only source of information (i.e., fossil taxa without living representatives) is the implementation of an integrative approach, combining different methodological techniques and a good description of specimens.

scholarly journals Where should we draw the lines between dinocyst “species”? Morphological continua in Black Sea dinocysts

2019 ◽  
Vol 38 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Thomas M. Hoyle ◽  
Manuel Sala-Pérez ◽  
Francesca Sangiorgi
Keyword(s):  
Black Sea ◽  
Genetic Difference ◽  
Morphological Variability ◽  
Intraspecific Variability ◽  
Nutrient Status ◽  
The Black Sea ◽  
Genetic Sequencing ◽  
Morphological Variations ◽  
Intermediate Phenotypes ◽  
Primary Driver

Abstract. The morphology of dinoflagellate cysts (dinocysts) is related not only to the genetics of the motile dinoflagellate from which it derives, but is also dependent on a range of environmental factors including salinity, temperature and nutrient status. Although this knowledge improves our understanding of the drivers behind dinocyst morphological variations, it makes the taxonomy governing their description somewhat complex. In basins such as the Black Sea, where environmental change can be extreme and occurs on relatively short (millennial) timescales, taxonomy becomes particularly challenging. Morphological continua can be observed between described forms, displaying a large range of intermediate phenotypes that do not necessarily correspond to any genetic difference. As these morphological nuances may preserve information about palaeoenvironments, it is important to find a systematic method of characterising morphotypes. Here, we show a dinocyst matrix within which dinocysts are described according to their similarity to (or difference from) described forms based on key descriptive parameters. In the example set out here, cyst shape and degree of process and/or ectophragm development are taken as two key parameters in Pyxidinopsis psilata and Spiniferites cruciformis, and can allow the description of intermediate forms even though the definitions do not overlap. We review some frequently occurring morphotypes and propose that using matrices to show the gradual variation between endmember forms is the most pragmatic approach until cyst–theca studies and genetic sequencing can be used to demonstrate relationships between genotypes and morphotypes. As prior studies propose salinity to be a primary driver of intraspecific variability, the endmembers presented may represent salinity extremes within an overall brackish environment. Although we cannot assign each morphotype to a value or a range of an environmental parameter (e.g. salinity) as the different morphotypes can occur in the same sample, using this matrix allows preservation of information about morphological variability without creating taxonomic categories that are likely to require alteration if genetic evidence becomes available.

scholarly journals Morphological variability of Quercus robur L. leaf in Serbia

Genetika ◽  
2017 ◽  
Vol 49 (2) ◽  
pp. 529-541
Author(s):  
Branislava Batos ◽  
Danijela Miljkovic ◽  
Marko Perovic ◽  
Sasa Orlovic
Keyword(s):  
Leaf Area ◽  
Analysis Of Variance ◽  
Population Differentiation ◽  
Quercus Robur ◽  
Phenotypic Variability ◽  
Morphological Variability ◽  
Intraspecific Variability ◽  
Morphological Characters ◽  
Interpopulation Variability ◽  
Intrapopulation Variability

This paper presents the results of a study dealing with leaf morphological variability of Quercus robur L. 148 trees were sampled from 5 population across Serbia and 17 morphological traits were assessed. Interpopulation variability was confirmed by the results of the analysis of variance (ANOVA). A statistically significant (p <0.05) effect of population was obtained for most of the studied morphological characters. Intrapopulation variability was confirmed by statistically significant tree effects for all of the studied leaf characters (all p < 0.05). The results of the multivariate analysis of variance (MANOVA) confirmed a significant population and tree share in the total phenotypic variability (all p <0.05). By applying the canonical discriminant analysis (CDA), the first discriminant function accounted for 63% of the variability between populations and the second accounted for 20% of the population variability. The leaf area (AREA), specific leaf area (SLA) and surface area to perimeter ratio (ARPE) had the greatest effect on population differentiation (CDA). It is assumed that different environmental conditions affect population differentiation and that high intrapopulation variability is due to intraspecific variability.

scholarly journals Factors mediating plastid dependency and the origins of parasitism in apicomplexans and their close relatives

2015 ◽  
Vol 112 (33) ◽  
pp. 10200-10207 ◽  
Author(s):  
Jan Janouškovec ◽  
Denis V. Tikhonenkov ◽  
Fabien Burki ◽  
Alexis T. Howe ◽  
Martin Kolísko ◽  
...  
Keyword(s):  
Plastid Genome ◽  
Sequence Data ◽  
Sister Group ◽  
Molecular Characteristics ◽  
Phylogenomic Analysis ◽  
Free Living ◽  
Plastid Genomes ◽  
Monophyletic Lineage ◽  
Causative Agents ◽  
Close Relatives

Apicomplexans are a major lineage of parasites, including causative agents of malaria and toxoplasmosis. How such highly adapted parasites evolved from free-living ancestors is poorly understood, particularly because they contain nonphotosynthetic plastids with which they have a complex metabolic dependency. Here, we examine the origin of apicomplexan parasitism by resolving the evolutionary distribution of several key characteristics in their closest free-living relatives, photosynthetic chromerids and predatory colpodellids. Using environmental sequence data, we describe the diversity of these apicomplexan-related lineages and select five species that represent this diversity for transcriptome sequencing. Phylogenomic analysis recovered a monophyletic lineage of chromerids and colpodellids as the sister group to apicomplexans, and a complex distribution of retention versus loss for photosynthesis, plastid genomes, and plastid organelles. Reconstructing the evolution of all plastid and cytosolic metabolic pathways related to apicomplexan plastid function revealed an ancient dependency on plastid isoprenoid biosynthesis, predating the divergence of apicomplexan and dinoflagellates. Similarly, plastid genome retention is strongly linked to the retention of two genes in the plastid genome, sufB and clpC, altogether suggesting a relatively simple model for plastid retention and loss. Lastly, we examine the broader distribution of a suite of molecular characteristics previously linked to the origins of apicomplexan parasitism and find that virtually all are present in their free-living relatives. The emergence of parasitism may not be driven by acquisition of novel components, but rather by loss and modification of the existing, conserved traits.

scholarly journals Not all that clear cut: intraspecific morphological variability inSqualus blainville(Risso, 1827) and implications for identification of the species

2015 ◽  
Vol 96 (8) ◽  
pp. 1585-1596 ◽  
Author(s):  
Juan José Bonello ◽  
Leanne Bonnici ◽  
Alice Ferrari ◽  
Alessia Cariani ◽  
Patrick J. Schembri
Keyword(s):  
Fisheries Management ◽  
Morphological Variability ◽  
Intraspecific Variability ◽  
Morphological Features ◽  
Cytochrome Oxidase Subunit ◽  
Clear Cut ◽  
Management Zone ◽  
Maltese Islands ◽  
Dorsal Fin ◽  
Mtdna Marker

Of the three species of the genusSqualusthat occur in the Mediterranean Sea,S. blainvilleandS. megalopsare very difficult to distinguish. This study assesses the variability in morphological features that have been used to differentiate between these species.Squaluswere collected from stations within the 25-nautical mile Fisheries Management Zone around the Maltese Islands; 349 specimens were dissected and categorized into male and female, mature and immature, and individuals were randomly selected from each category to make up a sample of 169 specimens. For each individual, total length and first dorsal fin parameters were measured, and morphology of denticles isolated from the laterodorsal area, of the upper and lower teeth and of the chondrocranium was analysed. The first dorsal spine was shorter that the fin base in 93% of the specimens, which is typical ofS. megalops; this character was not related to either gender or maturity. Chondrocrania with one lateral process (typical ofS. blainville) and two lateral processes (typical ofS. megalops) were present. Teeth from the same individuals showed morphological features that overlap betweenS. blainvilleandS. megalops. Both unicuspid (typical ofS. megalops) and tricuspid denticles (typical ofS. blainville) were observed on the same individuals. Twelve specimens (six having one and six having two lateral chondrocranial processes) were analysed genetically by sequencing of the mtDNA marker Cytochrome Oxidase Subunit I (COI). All resulted to beS. blainvilleshowing that intraspecific variability in supposedly diagnostic morphological features is large enough to render these unreliable to tell apart these two species, especially in the field.

A molecular phylogenetic analysis of genus Anevrina (Diptera: Phoridae), with the description of a new species and updated world key

Zootaxa ◽  
2010 ◽  
Vol 2397 (1) ◽  
pp. 29 ◽  
Author(s):  
PAUL T. SMITH ◽  
BRIAN V. BROWN
Keyword(s):  
Sister Group ◽  
Phylogenetic Study ◽  
Bayesian Analyses ◽  
Molecular Phylogenetic Study ◽  
Molecular Tree ◽  
Monophyletic Lineage ◽  
Molecular Phylogenetic ◽  
Branch Support ◽  
New Synonymy ◽  
A New Species

Here we report on the first molecular phylogenetic study of the phorid genus Anevrina using a combination of nuclear (28S) and mitochondrial (12S, ND1 and CO1) genes for a total of 2220bp. Both maximum parsimony and Bayesian analyses recovered Anevrina as a monophyletic lineage within a broad sampling of phorid taxa that included 13 genera from 4 subfamilies. The higher-level relationships of phorid taxa based on the molecular tree were (Sciadocerinae + ((Hypocerinae + Phorinae) + Metopininae))). Relationships of species within Anevrina were also fully resolved with strong branch support in the form of posterior probabilities, bootstrap values, and decay indices. Two major clades were identified within Anevrina: ((A. luggeri + A. macateei) + (A. curvinervis + A. unispinosa)), which was joined as a sister group to ((A. variabilis + A. thoracica) + (A. olympiae + A. urbana)). A new and first Neotropical species, A. neotropica, from Costa Rica is described, illustrated, and included in an updated world key. Anevrina setigera (Loew, 1874) is synonymized with A. urbana (Meigen, 1830), new synonymy.

Morphological variability and molecular characterization of Mawsonascaris australis (Johnston & Mawson, 1943) (Nematoda: Ascaridoidea: Acanthocheilidae) from the brown guitarfish Rhinobatos schlegelii Müller & Henle (Rhinopristiformes: Rhinobatidae)

2017 ◽  
Vol 92 (6) ◽  
pp. 760-764 ◽  
Author(s):  
W.-T. Zhao ◽  
Z. Xu ◽  
L. Li
Keyword(s):  
Internal Transcribed Spacer ◽  
Morphological Variability ◽  
Intraspecific Variability ◽  
Interspecific Variation ◽  
Fish Host ◽  
Molecular Approaches ◽  
The Taiwan Strait ◽  
The Right ◽  
First Time

AbstractA rare ascaridoid species, Mawsonascaris australis (Johnston & Mawson, 1943), is reported from the Taiwan Strait for the first time, and the brown guitarfish Rhinobatos schlegelii Müller & Henle (Rhinopristiformes: Rhinobatidae) represents a new fish host. The detailed morphology of M. australis was studied using light and scanning electron microscopy (SEM) based on the newly collected specimens. The results revealed some important, but previously unreported or erroneous, morphological features, including the lateral alae starting well posterior to the base of the ventrolateral lips, the presence of one pair of double paracloacal papillae and a single, small precloacal median papilla on the anterior margin of the cloaca. In addition, in order to determine whether the morphometric difference in the relative lengths of the right and left spicules represents intraspecific or interspecific variation, specimens of M. australis were characterized using molecular approaches by sequencing and analysing the ribosomal internal transcribed spacer (ITS) and mitochondrial cox1 genes. The results indicate that this morphometric difference represents intraspecific variability.

scholarly journals Genetic characterization of Genista sericea Wulfen (Cytiseae – Fabaceae) as revealed by nuclear DNA content and its nrDNA region analysis

2012 ◽  
Vol 71 (2) ◽  
pp. 195-205
Author(s):  
Liliana Vižintin ◽  
Vera Kosovel ◽  
Laura Feoli Chiapella
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
Morphological Variability ◽  
Geographic Origin ◽  
Nuclear Dna Content ◽  
Intraspecific Variability ◽  
Its Region ◽  
Its Nrdna ◽  
Morphological Differences ◽  
Northern Croatia

Summary-Genista sericeaWulfen, a northern Illyrian amphi-Adriatic species, presents a certain morphological variability. To clarify whether the genetic variations support the morphological differences among accessions of different geographic origin, analysis of nuclear DNA content and polymorphism of the internal transcribed spacer (ITS) dataset was studied. The variation in nuclear DNA content ofG. sericeavar.sericeaand var.rigidais minimal (2.09 and 2.08 pg/nucleus respectively) and is correlated with equal chromosome numbers in both varieties. Intraspecific variability of the ITS region was studied on 13 accessions ofG. sericea, 6 belonging to var.sericeaand 7 to var.rigida. These accessions were analyzed in comparison to closely related species already studied. ITS sequences ofG. sericearevealed large polymorphism and formed two main clusters. One cluster (6 accessions) comprehends var.sericeaof northern Italy, Slovenia and northern Croatia; the other cluster (7 accessions) includes five accessions of var.rigidafrom southern Croatia and Montenegro and two from the Pollino massif (southern Italy). The later two accessions considerably differed from other accessions of var.rigida. This genetic analysis supports the previous assumptions, which subdividedG. sericeainto at least two taxa. On the basis of the results presented, it is here suggested that the subdivision ofG. sericeainto var.sericeaand var.rigidashould be maintained.

scholarly journals Taxonomic problems in the subgenus Meloehelea Wirth of the genus Atrichopogon Kieffer (Diptera: Ceratopogonidae) inferred from both morphological and molecular characters

2008 ◽  
Vol 19 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Andrea Tóthová ◽  
Jan Knoz ◽  
Radim Sonnek ◽  
Josef Bryja ◽  
Jaromír Vaňhara
Keyword(s):  
Morphological Variability ◽  
Intraspecific Variability ◽  
Taxonomic Revision ◽  
Morphological Characters ◽  
Valid Species ◽  
European Species ◽  
Rdna Sequences ◽  
16S Rdna Sequences ◽  
Molecular Characters

The classification of Meloehelea (Ceratopogonidae) species is based on morphological characters. The taxonomic revision of generally well-known species recovered interesting facts on possible geographic intraspecific variability or on the presence of an additional valid species. In this study, 5 European species and 2 species from the U.S.A. and Canada have been compared based on their morphological characters. Subsequently, the 16S rDNA sequences analyses of well known European species have been performed to confirm the characters mentioned in the determination key ofthis subgenus. Although, this study was limited by the number of examined non-European specimens, it provides some interesting facts on the possible morphological variability of well-known species and also an initial phylogenetic backbone for the progressive reconstruction of infrageneric relationships within the genus Atrichopogon.

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